甾醇C-24甲基转移酶和甾醇C-8异构酶在酿酒酵母麦角甾醇生物合成中的调控作用  

Regulation role of sterol C-24 methyltransferase and sterol C-8 isomerase in the ergosterol biosynthesis of Saccharomyces cerevisiae

作　　者：张振颖[1,2] 何秀萍[1] 李巍巍[1,2] 卢莹[1] 王肇悦[1] 张博润[1] 

机构地区：[1]中国科学院微生物研究所,北京100101 [2]中国科学院研究生院,北京100101

出　　处：《微生物学报》2009年第8期1063-1068,共6页Acta Microbiologica Sinica

基　　金：国家自然科学基金(30470035)~~

摘　　要：[Objective] Ergosterol is a fungal metabolite with economic importance.For ergosterol biosynthesis,to identify the bottleneck enzymes in the metabolic pathway is of crucial importance.[Methods] Sterol C-8 isomerase encoding gene ERG2 was cloned from Saccharomyces cerevisiae by PCR.To evaluate the effect of ERG2 overexpression on the sterol content in the yeast,the expression plasmid pPERG2 was constructed and transformed into S.cerevisiae strain YS58 to generate recombinant strain YS58(pPERG2).In addition,the regulation role of sterol C-24 methyltransferase,encoded by ERG6,in ergosterol biosynthesis was further verified by analysis of sterol components and levels in yeast strains overexpressing ERG6,ERG2 respectively,or overexpressing ERG6 and ERG2 simultaneously.[Results] Ergosterol content and all sterol intermediates increased largely by overexpressing ERG6 in S.cerevisiae.Although the overexpression of sterol C-8 isomerase encoded by ERG2 alone had negative effect on ergosterol biosynthesis,overexpression of ERG6 and ERG2 simultaneously led to an increased ergosterol level,which was 1.41-fold of that in empty vector strain,1.92-fold of that in ERG2 only overexpressing strain and 1.12-fold of that in ERG6 only overexpressing strain.[Conclusion] These results demonstrated that sterol C-24 methyltransferase is an important bottleneck enzyme for ergosterol biosynthesis in S.cerevisiae.[ Objective] Ergosterol is a fungal metabolite with economic importance. For ergosterol biosynthesis, to identify the bottleneck enzymes in the metabolic pathway is of crucial importance. [ Methods] Sterol C-8 isomerase encoding gene ERG2 was cloned from Saccharomyces cerevisiae by PCR. To evaluate the effect of ERG2 overexpression on the sterol content in the yeast, the expression plasmid pPERG2 was constructed and transformed into S. cerevisiae strain YS58 to generate recombinant strain YS58（pPERG2）. In addition, the regulation role of sterol C-24 methyhransferase, encoded by ERG6, in ergosterol biosynthesis was further verified by analysis of sterol components and levels in yeast strains overexpressing ERC,6, ERG2 respectively, or overexpressing ERG6 and ERG2 simultaneously. [ Results] Ergosterol content and all sterol intermediates increased largely by overexpressing ERG6 in S. cerevisiae. Although the overexpression of sterol C-8 isomerase encoded by ERG2 alone had negative effect on ergosterol biosynthesis, overexpression of ERC,6 and ERG2 simultaneously led to an increased ergosterol level, which was 1.41-fold of that in empty vector strain, 1.92-fold of that in ERG2 only overexpressing strain and 1.12-fold of that in ERC,6 only overexpressing strain. [ Conclusion] These results demonstrated that sterol C-24 methyltransferase is an important bottleneck enzyme for ergosterol biosynthesis in S. cerevisiae.

关 键 词：甾醇C-24甲基转移酶 甾醇C-8异构酶 共表达 麦角甾醇 酿酒酵母 

分 类 号：Q936[生物学—微生物学]